拜耳濾鏡與交錯式掃描探討

大像幅相機在執行空照業務時，具有高效率之優點。在相同地元尺寸（地面解析力）時，其涵蓋面積與地面解析度之組合，較中、小像幅者為高。但是中、小像幅之製圖相機，相對上單價較低，操作與數據處理亦相對簡易。配合空載光達作業時，中像幅製圖相機是目前普遍之選擇。檢視目前市場上各種中像幅製圖相機，其彩色成像原理多運用拜耳濾鏡以獲取彩色影像，至於像元信號擷取方式則未見有使用交錯式掃描者。如以高速取像考量時，交錯式掃描當亦是一個可能選擇方式。本文謹回顧拜耳濾鏡與交錯式掃描基本原理，以及此兩項機制對影像品質之影響。並以實際現有型號之規格為例，探討應用於製圖時所需有之考量。 Large format camera has higher efficiency in the operation of aerial mapping. At the sameground resolution, when both the coverage and ground resolution are considered, the value of largeformat camera is significantly higher. However, the cost of equipment for medium format and smallformat cameras is relatively lower. The operation and data processing is less complicated as well.Medium format camera is the common choice for serving as the accompanying photographic deviceof airborne lidar. Reviewing the imaging scheme utilized in almost all current medium formatcameras, Bayer’s filter is a common feature. Interlaced scan is capable of doubling the samplingfrequency at the cost of spatial resolution. It is not utilized in the medium format mapping camera, but has the potential for being applied. This article reviews the fundamental concept andimplementation of Bayer’s filter and interlacing. The effect of these two schemes to the imageresolution is then explored. Examples are provided with the specification of several medium formatcameras in market.

Large format camera has higher efficiency in the operation of aerial mapping. At the sameground resolution, when both the coverage and ground resolution are considered, the value of largeformat camera is significantly higher. However, the cost of equipment for medium format and smallformat cameras is relatively lower. The operation and data processing is less complicated as well.Medium format camera is the common choice for serving as the accompanying photographic deviceof airborne lidar. Reviewing the imaging scheme utilized in almost all current medium formatcameras, Bayer’s filter is a common feature. Interlaced scan is capable of doubling the samplingfrequency at the cost of spatial resolution. It is not utilized in the medium format mapping camera,but has the potential for being applied. This article reviews the fundamental concept andimplementation of Bayer’s filter and interlacing. The effect of these two schemes to the imageresolution is then explored. Examples are provided with the specification of several medium formatcameras in market.